This invention relates to the structure of a bipolar type semiconductor device and a semiconductor integrated circuit device each having bipolar type and MIS type semiconductor devices as formed on the same substrate, and also relates to arrangements of semiconductor integrated circuit devices including a semiconductor integrated circuit device for use as a power supply having a constant voltage output function and a constant current output function.
Prior known bipolar type semiconductor devices are such that only a relatively thin oxide film is on the base region thereof while letting an interlayer insulating film and passivation film reside on the oxide film, which would result in occurrence of various influences onto the base region surface, which in turn can badly behave to enlarge variations in characteristics of such bipolar transistors and/or cause a change of the characteristics with time. In addition, since the base electrode region and emitter region are determinable by the oxide film's etching process and also position-determined by separate alignment procedures independent of each other, the resulting alignment steps increase in number thereby increasing an error in position alignment. Alternatively, the oxide film etching can sometimes result in an energy level or the like taking place in the interface between silicon and silicon oxide films of an emitter junction, which would reduce or degrade the characteristics. Furthermore, the currently available self-alignment technologies as widely employed until today are extremely complicated both in structure and in process increasing the number of process steps, which lengthens a time taken for effectuation of such processes required.
FIG. 2 is a diagram showing a cross-sectional view of a prior known bipolar transistor without having any polycrystalline silicon layer disposed on the surface of a base region so that the transistor is not self-aligned. An emitter region 32 and a base electrode 31 are not formed so that these are self-aligned with each other.
As has been described above, it has been revealed that in the bipolar type semiconductor devices, a fine or delicate change in structure and process in regard to the base region can significantly affect the resultant device characteristics. In addition, it remains impossible to easily reduce deviation in positional distance of respective impurity regions, which has served as the cause for deviation of h.sub.FE, breakdown voltage, frequency characteristics and the like--these are major properties of bipolar transistors--as well as threshold voltage thereof. This in turn makes it impossible to manufacture those devices of good characteristics by use of easy processes.
It is therefore an object of this invention to avoid the problems encountered with the prior art by providing a device of less deviation capable of manufacture by simple and low-cost processes.